Cardiac catheterisation is a minimally invasive surgery (MIS) procedure performed using flexible, thin and long tubes called catheters. The catheter is inserted through a small incision into the femoral vein which leads to the heart, and the goal is usually to reach specific locations inside the body (e.g. the heart) and to perform examinations or treatments such as RF ablations. The main advantages of using catheters are the reduced trauma and shorter recovery time for the patient, but conventional catheters usually have limited degrees of freedom, as the catheter can typically only rotate and slide through the trocar port.
Most commercial catheters at present consist of a flexible plastic body and a manoeuvrable tip that is manipulated with preconfigured guide wires or tendons. Example prior art catheters are disclosed in Yi et al “Multiturn, Tension Stiffening Catheter Navigation System”, Robotics and Automation (ICRA), 2010 IEEE International Conference, pp 5570-5575, and P. Canagaratnam et al “Experience of Robotic Catheter Oblation in Humans Using a Novel Remotely Steerable Catheter Sheath”, Journal of Interventional Cardiac Electrophysiology, Volume 21, pages 19 to 26, 2008, as well as in U.S. Pat. No. US RE40852, U.S. Pat. No. 4,586,923, and U.S. Pat. No. 6,980,843. In addition, imaging of conventional catheterisation procedures has typically been performed using x-ray fluoroscopy. However, this technique returns only 2D images with poor soft tissue contrast. To try and improve imaging during catheterisation procedures, and to reduce exposure to x-ray radiation, magnetic resonance imaging (MRI) techniques have started to be used but the use of magnetic resonance imaging requires that certain materials be used, and in particular non-ferrous and non-conductive materials.
To continue to improve and expand upon existing cardiac catheterisation techniques, there is a need for a catheter of increased steerability, and also manufactured from MR compatible materials.